1. Field of the Invention
The invention concerns a gear pump, especially for conveying paints according to the preamble of claim 1.
2. Description of Related Art
A generic gear pump is known from DE 10 2005 016 670 A1. The known gear pump has two intermeshing gears, which are mounted to rotate within a pump housing through a drive shaft and journal. The gears, together with a pump inlet and a pump outlet, form a feed channel system within the pump housing, in order to convey paint in liquid or powdered form. To prevent paint residues from emerging from the feed channel system through the gap formed between the pump housing and the gears and being distributed over the gap within the pump housing, seals are provided between the front faces of the gears and the pump housing. A flushing channel system is also formed within the pump housing, in order to flush out possible paint residues from the gaps between the pump housing, gears, drive shaft and journal during a paint change.
The known gear pump can already be recognized from the combination between front sealing of the gears and the subsequently arranged flushing channel system, in that such sealing systems, because of continuous friction, are subject to increased wear. To this extent, only limited sealing of the gap on the front faces of the gears relative to the fixed pump housing can be achieved. In addition, higher sealing forces in the front area of the gears would only lead to an undesired increase in drive power.
Another problem in the gear pump known in the prior art results from the fact that dead spaces are created by the connection devices arranged in the gap between the drive shaft and the gear, which cannot be freed of paint residues by flushing. Because of the rotational movement of the drive shaft and the gear, such paint residues, however, propagate in an undesired fashion, so that undesired contamination cannot be ruled out.
A gear pump is known from EP 1 164 293 A2, in which the feed channel system and the flushing channel system are connected within the pump housing only by the gap between the pump housing, the gears, the driveshaft and the journal. To this extent, the paint residues that reach the gap can be removed by intensive flushing. However, in the known gear pump, the driveshaft is connected to the gear by force-fit, which, however, hampers simple disassembly and assembly between the driveshaft and the gear.
The task of the invention is to modify a gear pump of the generic type, so that the gap connected to the feed channel system can be easily flushed within the pump housing.
Another objective of the invention is to provide a gear pump of the generic type, in which assembly and disassembly possibilities are retained even after longer operating times.